Beating a Dead Horse
Again, I can't stress enough how important this chess lesson is:
Learn it, live it, love it.
It's not that I am some brilliant chess scholar (far from it!), you can find this endgame analysis in any good chess book, but I am just absolutely amazed how many players don't know it.
Here is not one but two cases where opponents should have beaten me only to draw using the Dominant/Recessive Position moves. If they understood the basic principles, they would have won.